1. Field of the Invention
The present invention relates to an imaging device displaying a focusing-verification image for manual focus and a focusing-verification display method.
2. Description of the Related Art
As a digital camera, those having a so-called manual focus mode have been well known in which a user can manually adjust a focus, in addition to those of auto focus using a phase difference detection method and a contrast detection method.
As a digital camera having the manual focus mode, there have been well known those using a method of using a split microprism screen in which a reflex mirror is provided such that focus adjustment can be carried out while confirming an imaged subject to display a visual phase difference and a method of visually confirming contrast.
A digital camera with the reflex mirror being omitted which has spread in recent years has no method for confirming a subject image while displaying the phase difference because of the lack of the reflex mirror, and has had to depend on the contrast detection method. In this case, however, contrast cannot be displayed at a resolution beyond that of a display device such as a LCD or the like, and thus, there has been no choice but to take a method of displaying with a part being enlarged.
Therefore, in recent years, a split image (also referred to as a “focusing-verification image” in the description) is displayed in a live view image in order to facilitate an operation of an operator bringing the subject into focus in the manual focus mode. Here, the split image is obtained by compositing two subject images (phase difference image) acquired by pupil division picking up, and represents the phase difference of the subject image. In other words, the split image is displayed in which an upper half of one subject image and a lower half of the other subject image are arranged vertically adjacent to each other. The vertically adjacent two subject images are displayed with being horizontally displaced from each other in an out-of-focus state, and the vertically adjacent two subject images are displayed with no horizontal displacement in an in-focus state. The operator manipulates a focus ring for focusing such that the horizontal displacement between two subject images in the split image disappears.
A digital camera described in Japanese Patent Application Laid-Open No. 2004-40740 (hereinafter referred to as PTL 1) vertically moves a diaphragm and an optical axis to image a subject picture at each of two distance measurement positions and uses these two subject pictures to display a split image in a live view image.
A digital camera described in Japanese Patent Application Laid-Open No. 2001-309210 (hereinafter referred to as PTL 2) finds as a displacement amount a value corresponding to a distance between an image plane of a subject image and a light receiving surface of an image pickup device to display in a live view image a split image in which the subject images are displaced in horizontally opposing directions depending on this displacement amount.
Digital cameras described in Japanese Patent Application Laid-Open No. 2009-147665 (hereinafter referred to as PTL 3) and Japanese Patent Application Laid-Open No. 2009-163220 (hereinafter referred to as PTL 4) include an image pickup device having a plurality of normal pixels for imaging and a plurality of two kinds of phase difference pixels for focus detection arrayed on an image pickup surface, the phase difference pixel receiving a pupil-divided subject light. This digital camera generates a picked-up image on the basis of an output signal from the normal pixel to display a live view image and generates a split image on the basis of output from each of two kinds of phase difference pixels to display in the live view image.